Field of the Invention
The present invention relates to a new kind of a slide ring and a mechanical seal, a so called slide ring seal used, for example, for sealing a shaft space of a centrifugal pump in relation to a pumping space thereof. The present invention also relates to coupling said mechanical seal to a housing, to a shaft and to a rotor of a flow machine. Therefore, the present invention also relates to the shaft, the housing and the rotor of the flow machine.
In the following description of prior art and the present invention, a centrifugal pump has been used as an example of a flow machine, and an impeller as an example of a rotor of a flow machine. However, it must be understood that the present invention may be used in connection with any flow machine i.e. any liquid treating apparatus having a rotary shaft, which needs to be sealed in such a way that the liquid to be treated is not able to flow along the shaft out of the apparatus. Thus the flow machine includes, in addition to centrifugal pumps, also other pumps as well as mixers and agitators, just to name a few alternatives.
Background Information
The prior art includes various types of seals used for sealing a shaft of a flow machine, like a gland packing, a slide ring seal and a dynamic seal. The two first mentioned seal types are based on closing the gap via which a leakage might occur, whereas the operation of the dynamic seal is based on creating a pressure difference capable of preventing the leakage. The dynamic seal is specifically designed for fibrous slurries, but also fits well for clean, viscous, non-fibrous slurries and liquids containing large solids. The dynamic seal does not need external sealing water and does not leak.